Thimangu is a 7th Degree Kukkiwon certified blackbelt, 2nd Class International Taekwondo Master Instructor, and 2nd Class Dan/Poom Test Judge with more than 35 years of Taekwondo experience. Thimangu, who is also an experienced journalist, began practicing Taekwondo in 1986, following a mugging in his hometown Nairobi, Kenya. He attended Kenya Taekwondo Association’s main school, then headed by Grandmaster Mogg Yoon. Master Ernest Olayo Madanji, one of East Africa’s most highly regarded Taekwondo teachers, was his main instructor for four years.

Thimangu came to the United States in 1990 for university education. He earned his first-degree black belt in November 1993 under Grandmaster Dr. Duk Gun Kwon of Franklin Park, Ill. That year, Thimangu began to teach Taekwondo at the Kankakee Valley Park District in Illinois, a stint that lasted five years. During that period he also earned Taekwondo instructor and referee certifications, completed undergraduate studies, found work as a full-time journalist and earned a master’s degree.

Thimangu moved from Kankakee in 1998 to Indianapolis to work as an Associated Press newsman. A year later he relocated to Ohio for a newspaper reporting job and resumed his Taekwondo training under Master Sun Park of Cincinnati, with whom he tested for 3rd-degree Kukkiwon black belt certification. Thimangu moved to St. Louis in 2002 and began studying under Grandmaster Tae Hyen Park in Ballwin, Mo. In 2007 he tested for 4th degree blackbelt Kukkiwon certification under his senior teacher Grandmaster Kwon, and two years later qualified as a 3rd Class Kukkiwon International Taekwondo Master Instructor.

Thimangu earned his 5th degree Kukkiwon certification in 2012. In 2015 he attended a Kukkiwon course for 3rd Class Kukkiwon Dan/Poom Test judge certification. In 2017 he tested for 6th degree blackbelt Kukkiwon certification under Grandmaster Kwon. The same year he also earned promotion to 2nd Class Kukkiwon International Master Instructor certification. He earned 7th Dan in March, 2024.

Until early 2009, when he opened Arch Taekwondo, Thimangu was a reporter at the St. Louis Business Journal. He lives in St. Louis County with his wife, Rachel, and their children, Benjie and Eva.